I'm thinking that sport bands will be "cheap" - like under $49 cheap. They may even put the classic buckle leather strap in this price bracket as well to include a non-sport base option. I can see the leather loop being a bit more, but still under $79. I'm HOPING that the Milanese Loop and Link Bracelet options stay under $149, but I could see Apple reasonably asking as much as $299 for them. I don't think they will be as much as (or more than) the watch itself, which again, I'm thinking will be around $499.
I'm also a believer that the space black version will be the same price, but that may just be wishful thinking on my part.
If I can walk away with a 42mm Space Black SS w/ the matching link bracelet and a sport band for under $799 I'll be really happy. Not sure if I'm just dreaming though.